The present invention relates generally to stretch film wrapping apparatus which is used for wrapping stretch film material around palletized loads, products, articles, or packages disposed at a wrapping station of a stretch film wrapping facility, and more particularly to a new and improved film delivery system which dispenses prestretched film material from a stretch film supply roll that is mounted upon a film carriage assembly which, in turn, is mounted upon a vertically movable rotatable ring assembly through means of a suitable mounting plate, wherein the film delivery system comprises a new and improved brake mechanism which is operatively associated with the stretch film roll arbor upon which a stretch film supply roll is mounted so as to optimally predetermine, control, and balance the proper degree of tension or force-to-load parameters which are in effect being applied to or impressed upon the stretch film roll arbor, and the supply of stretch film material disposed upon a stretch film supply roll attached to the stretch film roll arbor and being dispensed from the stretch film supply roll, during a stretch film wrapping operation such that the tension or force-to-load parameters are substantially constant, or within a predetermined range of values, regardless of the amount of stretch film material remaining upon the stretch film material supply roll.
Powered apparatus, for wrapping film material around palletized loads, products, packages, or articles which are disposed at a wrapping station of a wrapping or packaging facility, are of course well-known, and apparatus of the aforenoted type are disclosed within several patent publications, such as, for example, U.S. Pat. No. 4,587,796 which issued on May 13, 1986 to Haloila, U.S. Pat. No. 5,517,807 which issued on May 21, 1996 to Morantz, and U.S. Pat. No. 5,787,691 which issued on Aug. 4, 1998 to Turfan et al. As disclosed, for example, within FIG. 1 of the present patent application drawings, which corresponds to FIG. 1 of the aforenoted U.S. Pat. No. 5,517,807, the disclosure of such patent being incorporated herein by reference, it is briefly noted that an article to be wrapped within film material is disclosed at A and is located, in effect, at a wrapping station disposed upon a conveyor 18. The disclosed plastic film wrapping apparatus is seen to further comprise a stationary frame assembly 10, and a vertically movable frame assembly 12 which is mounted upon the stationary frame assembly 10 so as to be vertically movable with respect to the stationary frame assembly 10 as well as the load or article A to be wrapped and disposed at the wrapping station upon the conveyor 18. In addition, a rotatable ring member 14 is rotatably mounted upon the vertically movable frame assembly 12 so as to be vertically movable therewith with respect to the stationary frame assembly 10 and the article or load A to be wrapped and disposed at the wrapping station upon the conveyor 18, as well as to be rotatable around a vertical axis 16 with respect to the vertically movable frame assembly 12, the stationary frame assembly 10, and the article or load A to be wrapped and disposed at the wrapping station upon the conveyor 18. A film carriage assembly 28, upon which a plastic film material supply roll 30 is disposed, is in turn mounted upon the rotatable ring member 14 by means of a suitable mounting bracket, plate, or the like 29. In this manner, as the vertically movable frame assembly 12 is moved through its vertical operating range, and as the rotatable ring member 14 is likewise rotated around the vertical axis 16, the plastic film material disposed upon the plastic film material supply roll 30 is dispensed and wrapped around the article or load A disposed at the wrapping station upon the conveyor 18 so as to wrap the article or load A as desired.
It has been noted or experienced that while the aforenoted exemplary wrapping apparatus have of course performed satisfactorily and have been commercially successful, the aforenoted wrapping systems have not always been able to control or compensate for different tension or force-to-load requirements or wrapping load or force parameters attendant the wrapping of different portions or regions of a particular load, package, article, or product being wrapped due, for example, to different configurations or physical characteristics of the load, package, article or product as they are encountered during different times of the wrapping cycle. In addition, it has also been noted or experienced that the aforenoted wrapping systems have not always been able to control or compensate for the vastly different force-to-load or tension characteristics that are generated and impressed upon the film material throughout a particular article or load wrapping cycle, or alternatively, the vastly different force-to-load or tension characteristics that are generated and impressed upon the film material during different article or load wrapping cycles, due to the vastly different amounts of film material disposed or remaining upon the film material supply roll. It is well-known that a full roll of film material generates different force-to-load or tension characteristics or parameters than a substantially empty roll of film material. It is also known that it is imperative to control such tension or force-to-load characteristics, values, or parameters in order to ensure that the film material is wrapped around and upon the load, article, package, or product being wrapped with the proper degree or level of tension.
It is also known that, in accordance with conventional film dispensing and wrapping systems, the plastic film dispensed or withdrawn from its film supply roll is often routed or threaded around a multiplicity of film carriage rollers in order to provide or define a requisite amount of friction or tension between the film and the operative drive components of the system so as to prevent film slippage, slackness, or the like. The multiplicity of carriage rollers, however, are usually disposed within a substantially complex array with respect to each other which unfortunately renders the initial routing or threading of the film therethrough, such as, for example, when a new plastic film supply roll is being installed upon the wrapping apparatus, quite tedious, time-consuming, and dangerous for operator or maintenance personnel. The complexity of the film routing or threading also sometimes leads to errors in the actual routing or threading of the film with respect to the proper film route or threading path defined through the carriage rollers, and still further, the tediousness and time-consuming properties or characteristics of such apparatus lead to substantial production downtime of the film wrapping apparatus or system.
Still further, in connection with the provision of the conventional carriage rollers as noted hereinbefore, in order to obtain the aforenoted requisite amount of friction between the carriage rollers and the plastic wrapping film being dispensed or withdrawn from its film supply roll, the outer peripheral surface portions of the carriage rollers are often conventionally provided with raised or embossed mechanical projections or friction-generating surface portions which are adapted to engage the plastic film so as to minimize any slippage of the film relative to the conveying carriage rollers. Slippage between the carriage rollers and the plastic film being conveyed thereby does nevertheless occur, and accordingly, minute amounts of film particles or film additives become separated from the film material as a result of the frictional forces generated by means of the aforenoted raised or embossed mechanical projections or friction-engaging surface portions of the carriage rollers acting upon the plastic film. The surface portions of the carriage rollers therefore tend to become clogged with such film particles or additives, and such particles or additives also tend to adhere to the surface portions of the carriage rollers thereby in effect rendering the same useless from a friction-generating point of view. Still yet further, the raised or embossed mechanical projections or friction-generating surface portions of the carriage rollers also tend to in effect etch or permanently emboss mirror images of their patterns into surface portions of the plastic film as the film is conducted or travels around the outer peripheral surface portions of the carriage rollers. This is undesirable in that such patterns, which are in effect etched, embossed, or impressed upon the plastic film by means of the carriage rollers, operatively interfere with the proper reading, for example, of bar-code type labels, which are often placed directly upon the palletized loads, products, packages, or articles before the same are wrapped within the plastic wrapping film so as to enable or facilitate down-stream routing, transporting, or sorting of the palletized loads, products, packages, or articles, in view of the fact that the etched, embossed, or impressed patterns tend to scatter ambient light thus rendering the bar-code type labels unreadable.
A need therefore exists in the art for a new and improved film delivery system which can dispense film material from a film material supply roll in such a manner that the tension or force-to-load characteristics or parameters generated or impressed upon the film material can be maintained substantially constant or within a predetermined range of values regardless of any variable configurations or physical characteristics of the load, package, article or product being wrapped, and/or concomitantly, regardless of the different amounts of film material that are disposed or that remain upon the film material supply roll as the film material is dispensed from the film material supply roll during a particular article or load wrapping cycle, or alternatively, during different article or load wrapping cycles. An additional need exists in the art for a carriage roller assembly which renders the routing or threading of the plastic film therearound relatively simple, quick, safe for installation or maintenance personnel, and less tedious and time-consuming, and in addition, provides the necessary or requisite amount of friction drive with respect to the dispensed or tensioned film without adversely affecting or marring the surface portions or characteristics of the plastic film so as to enable the wrapped products, packages, loads, or articles to nevertheless be routed, sorted, or transported by means of, for example, bar-code reading techniques and apparatus.
Accordingly, it is an object of the present invention to provide a new and improved stretch film wrapping apparatus for wrapping stretch film material around palletized loads, products, articles, or packages, and a new and improved film delivery system incorporated within such apparatus.
Another object of the present invention is to provide a new and improved stretch film wrapping apparatus for wrapping stretch film material around palletized loads, articles, products, or packages, and a new and improved film delivery system incorporated within such apparatus wherein such apparatus and the film delivery system thereof effectively overcome the various aforenoted operational drawbacks characteristic of conventional or prior art apparatus or systems.
An additional object of the present invention is to provide a new and improved stretch film wrapping apparatus for wrapping stretch film material around palletized loads, articles, products, or packages, and a new and improved film delivery system incorporated within such apparatus wherein such apparatus and the film delivery system thereof effectively overcome the various aforenoted operational drawbacks characteristic of conventional or prior art apparatus or systems by providing a means for substantially generating constant force-to-load tension characteristics or parameters upon the film material during a wrapping cycle regardless of particularly unique structural configurations of the loads, products, articles, or packages being wrapped, or regardless or independent of the amount of stretch film material disposed or remaining upon the stretch film material supply roll.
A further object of the present invention is to provide a new and improved stretch film wrapping apparatus for wrapping stretch film material around palletized loads, articles, products, or packages, and a new and improved film delivery system incorporated within such apparatus wherein such apparatus and the film delivery system thereof effectively overcome the various aforenoted operational drawbacks characteristic of conventional or prior art apparatus or systems by providing an automatically compensating braking mechanism which is operatively connected to the stretch film supply roll arbor, upon which the stretch film supply roll is mounted, for substantially generating constant force-to-load tension characteristics or parameters upon the film material during a wrapping cycle regardless of particularly unique structural configurations of the loads, products, articles, or packages being wrapped, or regardless or independent of the amount of stretch film material disposed or remaining upon the stretch film material supply roll.
A yet further object of the present invention is to provide a new and improved stretch film wrapping apparatus for wrapping stretch film material around palletized loads, articles, products, or packages, and a new and improved film delivery system incorporated within such apparatus wherein such apparatus and the film delivery system thereof effectively overcome the various aforenoted operational drawbacks characteristic of conventional or prior art apparatus or systems by providing an automatically compensating braking mechanism which is operatively connected to the stretch film supply roll arbor, upon which the stretch film supply roll is mounted, and wherein further, such apparatus and the film delivery system thereof comprises a single idler or dancer roller assembly which simplifies the routing or threading of the plastic film material therearound and which does not adversely etch, emboss, impress, or mar the surfaces of the plastic film so as not to, in turn, compromise the readability of bar-code type labels secured upon the wrapped loads, packages, products, or articles.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved prestretched film wrapping apparatus for wrapping prestretched film material around palletized loads, articles, products, or packages, and a new and improved film delivery system incorporated within such apparatus, wherein such apparatus and the film delivery system thereof comprises a brake hub or pulley which is rotatably mounted upon a mounting plate of a film carriage assembly. The film carriage assembly is mounted upon a rotatable ring member which is mounted upon a vertically movable frame member of the film wrapping apparatus. A film roll arbor, upon which a film supply roll is fixedly mounted, is in turn fixedly mounted upon the brake hub or pulley, and a single idler or dancer roller is mounted for linear movement upon the mounting plate by means of spring-biased track or channel assemblies. The idler or dancer roller is also operatively connected to a first end of a brake arm which is pivotally mounted at its second opposite end upon the mounting plate, and a brake band is adapted to be disposed around an outer peripheral portion of the brake hub or pulley. A first end of the brake band is connected to a first end of a brake cable, while a second opposite end of the brake cable is fixedly connected to the second end of the brake arm. In a similar manner, a first end of a brake adjustment spring is connected to the second end of the brake band, while a second end of the brake adjustment spring is connected to an adjustment mechanism which is fixedly mounted upon the mounting plate. The prestretched film is withdrawn from its supply roll mounted upon the film arbor, routed around the idler or dancer roller, and conducted toward the load, package, product, or article being wrapped.
When the rotatable ring member of the wrapping apparatus is rotated, the idler or dancer roller is moved against the biasing forces of its channel or track-mounted spring members causing, in turn, pivotal movement of the brake arm so as to effectively release the brake band from its engaged position with the brake hub whereby the prestretched film is permitted to be dispensed. When rotation of the rotatable ring member of the wrapping apparatus is terminated, the channel or track-mounted spring members cause the idler or dancer roller to be moved toward its initial position at which position the brake arm is, in turn, caused to be moved toward its initial position whereby the brake band again engages the brake hub so as to arrest further dispensing of the prestretched film from the film supply roll. During a particular wrapping cycle, any variable forces operating upon the film material, either as a result of particular structural configurations or the like of the load, package, product, or article being wrapped, or as a result of the amount of film disposed or remaining upon the film supply roll, are automatically compensated for by means of the spring-biased idler or dancer roller as determined by means of the biasing forces of its channel or track-mounted spring members as well as the initial adjustment of the brake cable-brake band-adjustment brake spring assembly. In addition, as a result of the provision of a single idler or dancer roller assembly, the routing or threading of the prestretched film around the idler or dancer roller assembly is simplified and rendered relatively safe and quick. Still further, as a result of providing the outer peripheral surface portions of the idler or dancer roller with a highly-polished mirror-type surface finish to which the prestretched film can effectively adhere under atmospheric conditions, no mechanical projections or friction-generating surface embossments are required to be provided upon the idler or dancer roller in order to in effect frictionally engage and drive the prestretched film as the same is being dispensed from its film supply roll upon the film carriage assembly.